Problems to register a new contact in address book

Hello,

I've been trying to use the u3DXT framework for a few days to add a new contact in to address book. I've tried several approches, but none of them worked. Here is the "best" code I have so far:

 public void AddContact() {
     Debug.Log ("Will add contact");
 
     var book = ABAddressBook.Create ();
     var person = ABPerson.Create ();

     var firstname = new CFType(null, "Firstname");
     var lastname = new CFType(null, "Lastname");
 
     person.SetValue (ABPerson.kABPersonFirstNameProperty, firstname, null);
     person.SetValue (ABPerson.kABPersonLastNameProperty, lastname, null);
 
     book.AddRecord (person, null);
 
     bool success = book.Save (null);
     Debug.Log ("Success ?" + success);
 }

This code adds a contact in the address book, but it has no info, and is registered as "No name". Am I missing something?